In marine applications such as minesweeping, it is desirable to conduct high amperage electrical currents through a sweep cable being dragged through the water. The I.sup.2 R heating effect resulting from such high amperage currents causes degradation of the insulation of the electrical conductors and stands as a barrier to improved minesweeping operation requiring substantially higher currents than those which the present minesweeping cables are capable of handling.
Such sweep cables additionally must be buoyant so as to have a density of less than about 0.95, while resisting tensile stresses. Further, it is necessary to avoid abrasion of the outer surface of the cables as may result from dragging of the cables.
It is further necessary to provide high electrical resistance between the electrical conducting elements and the surrounding seawater.
It is further necessary to minimize the size of the cable and preferably provide such a sweep cable having a diameter of no more than 4 inches.
While increasing the diameter of the individual electrical conductors serves to lower the resistance and, thus, I.sup.2 R heating effect, constraints of buoyancy and cable diameter, as discussed above, have made this approach generally ineffective.
Another approach would be to increase the thermal conductivity while decreasing the thickness of the cladding or sheathing of the cable. The abrasion problem, however, places severe constraint on this approach.
Another possible approach is to provide the electrical conductor formed of materials having lower electrical resistance per unit weight. One such candidate material is a light, highly conductive polymer, such as polyacetylene. However, such currently available materials are relatively thermally unstable and present difficulties in mechanical process thereof in the manufacture of the cable.